This invention relates to flexible pipe couplings which are used for the connection of, for example, sewage pipes, gas pipes and the like to be embedded in ground and which are capable of accepting a displacement between the opposed connection pipes due to ground subsidence or the like.
A known coupling for underground pipes uses a bellows pipe, which is small in its acceptable displacement quantity per unit length. In order to accept a large displacement, the length of the bellows pipe must be lengthened, so that such a pipe has drawbacks in that the cost of the coupling is high and the workability becomes poor.
An attempt has been made to accept the large displacement between the opposed connection pipes by using as shown in FIG. 1 a flexible pipe coupling comprising a large diameter cylindrical hollow body a, a pair of small diameter cylindrical hollow bodies b.sub.1, b.sub.2 each having one end portion disposed inside each end of the large diameter cylindrical hollow body a on the same axial line, and an elastic sleeve member c for connecting each end of the large diameter cylindrical hollow body a to one end of each of the small diameter cylindrical hollow bodies b.sub.1, b.sub.2. However, such a coupling frequency causes trouble in durability for practical use.